The embodiments herein relate to methods of forming facsimile formation core samples using three-dimensional printing and, more particularly, to forming facsimile formation core samples that replicate either or both of the internal and external anatomy of a formation using three-dimensional printing.
Subterranean formation operations (e.g., stimulation operations, sand control operations, completion operations, etc.) often involve drilling a wellbore in a subterranean formation. The wellbore (e.g., vertical, deviated, and horizontal wellbores) is generally drilled using a drilling fluid pumped down a drill string and through a drill bit attached to the end of the drill string. The drilling fluid serves, among other things, to lubricate and cool the cutting surfaces of the drill bit, transport drill cuttings to the surface, control formation pressure, and maintain well stability.
In various oil and gas exploration operations, it is desirable to have available information about the composition and/or structure of the subterranean formation into which the wellbore is penetrated. Such information may be used to, among other things, determine the permeability of the formation, determine the porosity of the formation (i.e., the reservoir storage capacity), determine the compatibility of fluids used to perform subterranean formation operations, and the like. Such determinations may be essential to predicting the specific operational parameters for certain operations, estimating the productivity of the formation, approximating the lifetime of the formation, estimating the water content of the formation, and the like. Typically, in order to obtain such information, a downhole tool is employed that collects formation core samples. The downhole tool is generally a coring tool that hollows through the wall of the wellbore and into the formation for collecting a core sample, which is thereafter removed to the surface. Such formation core samples are typically obtained during or directly after drilling operations. Accordingly, they are generally limited to full-diameter core samples that are taken during drilling and are about the diameter of the drill bit, or sidewall core samples that are taken after drilling and are less than the full diameter of the drill bit.
In the case of full-diameter core samples, the drill string must be removed from the wellbore at some point during drilling operations in order to permit the coring tool to be penetrated therein. After the full-diameter core sample is removed, the coring tool must then be removed from the wellbore and drilling operations again commenced. In the case of sidewall core samples, the coring tool must be introduced into the wellbore after the full wellbore has been drilled and the drill string removed. In both cases, the amount of formation core samples is limited in terms of sample availability, time, and expense. Accordingly, only a relatively small subset of formation core samples is gathered for any particular wellbore in a subterranean formation. The relatively small subset of formation core samples translates into a reduced number of analyses that can be performed on each sample, particularly when testing is or may be destructive. As such, a full picture of the properties of the subterranean formation penetrated by a particular wellbore may not be possible.